https://bugs.gentoo.org/show_bug.cgi?id=539124
Excerpt:
Primarily, the idea here that a maintainer may want to have IUSE="foo bar"
and bar is recommended if foo is selected. Currently, the only way to
recommend a use flag is IUSE="+baz" This doesn't work with the above
mentioned example because IUSE="foo +bar" would recommend bar regardless of
whether foo is selected or not.
For backwards compatibility, the IUSE + syntax can be maintained, but
alternatively, it may be simpler, and make more sense to have something
like:
IUSE="foo bar baz"
RECOMMENDED_USE="
foo? ( bar )
baz"
So in this example:
IUSE="baz"
RECOMMENDED_USE="baz"
is equivalent to IUSE="+baz"
The original inspiration for this idea was the following,
app-emulation/wine works both with and without X. Most users who use X
would most likely want the USE flags lcms and xcomposite, but setting them
+ in IUSE makes compiling wine with -X more complicated, as every flag that
+ just for X users would have to be unset for non-X users. The above
system simplifies this by only setting + on lcms and xcomposite if X is set.
Alternatively, other names could be used, like DEFAULT_USE instead of
RECOMMENDED_USE, but that is a side note to the primary point.
Any thoughts on the idea would be greatly appreciated, and thank you in
advance for your time.
